Field-glass.



No. 802,317. PATBNTED-OGT.. 24, 1905.. A. J. LLOYD.

HELD GLASS.

APPLICATION `ILEI) MAR-29. 1905.

WITNEEEEEI- ANDREW J. LLOYD, OF BOSTON, MASSACHUSETTS.

FlELD-GLASSn Specification of Letters Patent.

Patented Oct. 24, 1905.

Application flied March 29, 1905, Serial No. 252,748.

To all, whom it may concern.-

Be it known that I, ANDREW J. LLOYD, a

citizen of the United States, residing at Boston, in the county ofSuffolk and State of Massachusetts, have invented anew and useful'Improvcment in Field-Glasses, of which the following', taken inconnection with the accompanying drawings, is a specification.

My invention relates to the focus adjustment of field or opera glasses;and it consists of va mechanism which will permit of adjusting eacheyepiece to the users eye, allowing for the focal characteristics ofeach eye, and then moving both eyepieces to adapt the combined eyepiecesto the distance of the object to be observed. The mechanism forobtaining this result is illustrated in the accompanying drawings, inwhich- Figure l shows in elevation a field-glass of the Zeiss class.Fig. Q shows an end view of the same. Fig. 3 is asectional view showingthe eyepieces and their connected parts.

In the drawings, A and B represent the body parts of the instrument, andGr and Gr the eyepieces, or, rather, the parts that are moved inadjusting the focal lengths to the different eyes and also to thedistance of the object to be observed.

K and K are sprocketed rings connected to the eyepieces and adapted toengage with the sprocket-chain L, whereby the turning of one of theeyepieces will cause a corresponding rotation of the other.

To adapt the instrument to the interocular distance, the parts A and Bare connected together by pivoted bars O O', and D D'. The parts C and Oand D and D overlap each other, as shown in Figs. 1 and 3, and areclamped together by means of the central tube E and a screw-rod E. rTheloosening of the screw-rod E will free the parts C and O' and also theparts D and Dl and admit of adjusting the distance between the bodyparts A B- that is, theinteroculardistance-and by tighteningl thescrew-rod E' the parts may be firmly held in the desired positions.

To adjust the separate eyepieces to the eyes, the spiral grooves H H aremadein the movable tubular parts and pins are set in the correspondingiixed tubes and are adapted to engage with the said grooves H and H', sothat by turning the external parts of the eyepieces the adjustment forthe individual eye is made.

The length of the sprocket-chain is adapted to the sprocketrings whenthe interocular distance is greatest. Vhen the body parts A and B arebrought nearer to each other in adjusting them to a shorter interoculardistance, the chain L will be slack, but not enough to prevent itsworking, as the sprocket-teeth are made comparatively long, and althoughthe chain is slack it will still perform its function.

In practice the eyepieces are adjusted to the characteristics of theusers eyes before the sprocket-chain L is connected to the instrument.Then the chain is placed upon its sprockets and theIield-glass isadjusted to the distance of the objects to be observed. Thus thepersonal adjustment remains permanent and is not affected by theobject-distance adj ustment.

I claim- In a binocularinstrumentof this class; eyepieces independentlyadjustable having' attached sprocketed rings; and a sprocket-chainconstructed to engage with said sprocketed rings; substantially as andfor the purpose set forth.

In testimony whereof I have signed my name to this specilication, in thepresence of two subscribing witnesses, on this th day of March,

ANDREW J. LLOYD. Witnesses:

FRANK G. PARKER, JOHN BUCKLER.

